Required practicals Flashcards
RP2- Calculating mitotic index of root cells.
Why is the onion/ garlic bulb suspended in water?
To stimulate cell division
RP2- Calculating mitotic index of root cells.
Why is root tip placed in ethanoic alcohol?
To stabilise the chromosomes
RP2- Calculating mitotic index of root cells.
Why is root tip placed in HCL and heated for 5 mins at 60 degrees
Helps separate cells by breaking down intracellular molecules
RP2- Calculating mitotic index of root cells.
Why are roots rinsed in water for 5 mins
To remove any HCL- ensuring chromosomes are not damaged
RP2- Calculating mitotic index of root cells.
Why are root tips pushed hard down on and why can no sliding occur
To ensure light can penetrate the cells- thin layer
Sliding will damage chromosomes
RP1- Investigation into the effect of a named variable on the rate of enzyme-controlled reaction
How will temperature be maintained
Use a thermostatically controlled water bath
RP1- Investigation into the effect of a named variable on the rate of enzyme-controlled reaction
How will amount of enzyme be controlled?
Use enzyme solutions of known concerntrations
Keep enzymes in same favourable conditions when storing
RP3- Production of a dilution series of a solute to produce a calibration curve to identify the water potential of plant tissue
Why can’t chips be too large?
Wont fit into tubes
RP3- Production of a dilution series of a solute to produce a calibration curve to identify the water potential of plant tissue
Why cant chips be too small?
Small inaccuracies are a higher proportion when dimensions are small
Calculating degrees of freedom Chi squared
Number of classes-1
Degrees of freedom Student T test
(n1-1) + (n2-1)
RP4- Investigation into named variable on cell membrane permeability
Why is beetroot washed before being added?
Removes pigment from damaged cells
Only pigment that leaves cells via membranes will be measured
RP4- Investigation into named variable on cell membrane permeability
Suggest why cylinders are 65 mm long
Enough cells to detect change in pigment
Not too big that beetroot wouldnt fit
RP4- Investigation into named variable on cell membrane permeability
Suggest why 25 cm^3 of water is added to each test tube
Enough to cover all beetroot cells
Not too much that the pigment is very diluted
RP4- Investigation into named variable on cell membrane permeability
Suggest why 25 cm^3 of water is added to each test tube
Enough to cover all beetroot cells
Not too much that the pigment is very diluted